Sexual cranial dimorphism in malnourished rats treated with growth hormone

One hundred and sixty two Holtzman rats of both sexes were malnourished during suckling and post-weaning periods. Some of them received periodic injections of growth hormone. After sampling, at 56 days of age, skulls were cleaned and measured. Differences within and between sexes were estimated by Mahalanobis D2 distances. Normal cranial differentiation between sexes (SCD) was decreased by malnutrition and restored by growth hormone treatment. The effect of the growth hormone on skull size was larger in malnourished males than females. This differential increment between sexes explains how growth hormone acted on the restoration of SCD.